/*
 *     .============.
 *    //  M A K E  / \
 *   //  C++ DEV  /   \
 *  //  E A S Y  /  \/ \
 * ++ ----------.  \/\  .
 *  \\     \     \ /\  /
 *   \\     \     \   /
 *    \\     \     \ /
 *     -============'
 *
 * Copyright (c) 2018 Hevake and contributors, all rights reserved.
 *
 * This file is part of cpp-tbox (https://github.com/cpp-main/cpp-tbox)
 * Use of this source code is governed by MIT license that can be found
 * in the LICENSE file in the root of the source tree. All contributing
 * project authors may be found in the CONTRIBUTORS.md file in the root
 * of the source tree.
 */
#include "aes.h"

namespace tbox {
namespace crypto {

//! 参考了第三方的实现，并进行了C++语法化

namespace {

const uint8_t Sbox[256] = {
   /*  0     1     2     3     4     5     6     7     8     9     a     b     c     d     e     f */
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, /*0*/
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, /*1*/
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, /*2*/
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, /*3*/
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, /*4*/
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, /*5*/
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, /*6*/
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, /*7*/
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, /*8*/
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, /*9*/
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, /*a*/
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, /*b*/
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, /*c*/
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, /*d*/
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, /*e*/
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16  /*f*/
};

const uint8_t InvSbox[256] = {
   /*  0     1     2     3     4     5     6     7     8     9     a     b     c     d     e     f */
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, /*0*/
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, /*1*/
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, /*2*/
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, /*3*/
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, /*4*/
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, /*5*/
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, /*6*/
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, /*7*/
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, /*8*/
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, /*9*/
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, /*a*/
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, /*b*/
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, /*c*/
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, /*d*/
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, /*e*/
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d  /*f*/
};

uint8_t FFmul(uint8_t a, uint8_t b)
{
    uint8_t bw[4];
    uint8_t res = 0;
    bw[0] = b;

    for (int i = 1; i < 4; i++) {
        bw[i] = bw[i - 1] << 1;
        if (bw[i - 1] & 0x80) {
            bw[i] ^= 0x1b;
        }
    }
    for (int i = 0; i < 4; i++) {
        if ((a >> i) & 0x01) {
            res ^= bw[i];
        }
    }

    return res;
}

void SubBytes(uint8_t state[][4])
{
    for (int r = 0; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            state[r][c] = Sbox[state[r][c]];
        }
    }
}

void ShiftRows(uint8_t state[][4])
{
    uint8_t t[4];

    for (int r = 1; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            t[c] = state[r][(c + r) % 4];
        }
        for (int c = 0; c < 4; c++) {
            state[r][c] = t[c];
        }
    }
}

void MixColumns(uint8_t state[][4])
{
    uint8_t t[4];

    for (int c = 0; c < 4; c++) {
        for (int r = 0; r < 4; r++) {
            t[r] = state[r][c];
        }
        for (int r = 0; r < 4; r++) {
            state[r][c] = FFmul(0x02, t[r]) ^ FFmul(0x03, t[(r + 1) % 4])
                          ^ FFmul(0x01, t[(r + 2) % 4]) ^ FFmul(0x01, t[(r + 3) % 4]);
        }
    }
}

void AddRoundKey(uint8_t state[][4], uint8_t k[][4])
{
    for (int c = 0; c < 4; c++) {
        for (int r = 0; r < 4; r++) {
            state[r][c] ^= k[r][c];
        }
    }
}

void InvSubBytes(uint8_t state[][4])
{
    for (int r = 0; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            state[r][c] = InvSbox[state[r][c]];
        }
    }
}

void InvShiftRows(uint8_t state[][4])
{
    uint8_t t[4];

    for (int r = 1; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            t[c] = state[r][(c - r + 4) % 4];
        }
        for (int c = 0; c < 4; c++) {
            state[r][c] = t[c];
        }
    }
}

void InvMixColumns(uint8_t state[][4])
{
    uint8_t t[4];
    for (int c = 0; c < 4; c++) {
        for (int r = 0; r < 4; r++) {
            t[r] = state[r][c];
        }
        for (int r = 0; r < 4; r++) {
            state[r][c] = FFmul(0x0e, t[r]) ^ FFmul(0x0b, t[(r + 1) % 4])
                          ^ FFmul(0x0d, t[(r + 2) % 4]) ^ FFmul(0x09, t[(r + 3) % 4]);
        }
    }
}

}

AES::AES(const uint8_t *key)
{
    if (key != nullptr)
        keyExpansion(key);
}

void AES::setKey(const uint8_t *key)
{
    keyExpansion(key);
}

void AES::cipher(const uint8_t *input, uint8_t *output)
{
    uint8_t state[4][4];

    for (int r = 0; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            state[r][c] = input[c * 4 + r];
        }
    }

    AddRoundKey(state, w[0]);

    for (int i = 1; i <= 10; i++) {
        SubBytes(state);
        ShiftRows(state);
        if (i != 10)
            MixColumns(state);
        AddRoundKey(state, w[i]);
    }

    for (int r = 0; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            output[c * 4 + r] = state[r][c];
        }
    }
}

void AES::invcipher(const uint8_t *input, uint8_t *output)
{
    uint8_t state[4][4];

    for (int r = 0; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            state[r][c] = input[c * 4 + r];
        }
    }

    AddRoundKey(state, w[10]);
    for (int i = 9; i >= 0; i--) {
        InvShiftRows(state);
        InvSubBytes(state);
        AddRoundKey(state, w[i]);
        if (i) {
            InvMixColumns(state);
        }
    }

    for (int r = 0; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            output[c * 4 + r] = state[r][c];
        }
    }
}

void AES::keyExpansion(const uint8_t *key)
{
    const uint8_t rc[] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };

    for (int r = 0; r < 4; r++) {
        for (int c = 0; c < 4; c++) {
            w[0][r][c] = key[r + c * 4];
        }
    }

    for (int i = 1; i <= 10; i++) {
        for (int j = 0; j < 4; j++) {
            uint8_t t[4];
            for (int r = 0; r < 4; r++) {
                t[r] = j ? w[i][r][j - 1] : w[i - 1][r][3];
            }
            if (j == 0) {
                uint8_t temp = t[0];
                for (int r = 0; r < 3; r++) {
                    t[r] = Sbox[t[(r + 1) % 4]];
                }
                t[3] = Sbox[temp];
                t[0] ^= rc[i - 1];
            }
            for (int r = 0; r < 4; r++) {
                w[i][r][j] = w[i - 1][r][j] ^ t[r];
            }
        }
    }
}

}
}
